Surface of the tongue
This study unit will help you to:
- Describe the structures and parts of the tongue.
- Name the function and innervation of its structures.
- Identify the four lingual papillae and distinguish their purpose.
The tongue consists of a body, apex and root containing the lingual papillae and tonsils. The body is bordered anteriorly by the apex and posteriorly by the root.
- Body of the tongue: contains the lingual papillae (filiform, fungiform, vallate and foliate papillae), which contain taste buds, except for the filiform papillae.
- Apex of the tongue: forms the anteriormost portion of the tongue.
- Root of the tongue: is the most posterior portion of the tongue and anchors the tongue to the mandible and hyoid bone. It contains the lingual tonsils and is separated by a “v-shaped” terminal sulcus from the body of the tongue.
The lingual papillae are located on the presulcal part of the tongue, just anterior to the terminal sulcus. The vallate papillae run parallel to the terminal sulcus, whereas the foliate papillae are located on the posterolateral end of the body of the tongue on each side. The filiform papillae are the most numerous lingual papillae and cover most of the presulcal area of the dorsum of the tongue. Their main function is to increase the friction between the food and the tongue. The fungiform papillae are larger than the filiform papillae and rounder in shape. They are mostly found at the tip and side of the tongue and contain taste buds on their upper surface.
Taste sensation is transmitted to the brainstem via three nerves: the facial nerve (chorda tympani) innervating the anterior ⅔ of tongue and soft palate, the glossopharyngeal nerve innervating the posterior ⅓ of the tongue and the vagus nerve innervating the epiglottis.
Take a quiz
Go ahead and test your newly gained knowledge on the surface of the tongue with our quiz.
If you would like to challenge yourself even further, try our custom quiz and solidify your knowledge of the oral cavity.
|Parts||Body, apex, root|
|Surfaces||Dorsal (superior) and ventral (inferior)|
|Papillae||Filiform, fungiform, foliate, vallate|
Hypoglossal nerve (CN XII): provides motor innervation to all muscles of the tongue, except palatoglossus muscle (vagus nerve (CN X))
Lingual nerve: conveys general somatic afferent impulses from anterior two-thirds of tongue
Glossopharyngeal nerve (CN IX): carries general afferent impulses from vallate papillae along posterior third of tongue, as well as taste sensation from postsulcal tongue, vallate papillae, palatoglossal arche and oropharynx
Facial nerve (CN VII): taste sensation of anterior two-thirds of tongue and inferior part of soft palate
Vagus nerve (CN X): provides taste buds in extreme areas of pharyngeal tongue
|Mucosa||Stratified squamous keratinized (dorsal surface) and non-keratinized (ventral surface) epithelium|
|Filiform papillae||Stretched, conical, gray-white papillae
Covered with keratinized squamous epithelium
Provide friction to allow movement of the food bolus during chewing
Do not possess taste buds
|Fungiform papillae||Highly vascular, mushroom-shaped papillae
Scattered across the entire dorsal surface of the tongue
Contain few taste buds on the apical aspect
|Foliate papillae||Bilaterally paired, parallel, “leaf-like” ridges of mucosa
On the posterolateral margin of the tongue, near the terminal sulcus
Contain numerous taste buds
|Vallate papillae||Usually between 8-12 cylindrical papillae
Anterior and parallel to the terminal sulcus of the tongue